Eubacteria, also known simply as "bacteria," can be found in every habitat on Earth. These organisms are widely varied and very adaptable, causing many illnesses in humans but also carrying out many helpful processes as well.
One way eubacteria can be identified is by their use of oxygen. Those that use oxygen or thrive in oxygen- rich environments are called aerobic while those that do not are called anaerobic. Some eubacteria are able to create endospore, which allow them to survive in very harsh conditions. Because of this, eubacteria can be found even in frozen, hot, radioactive or chemically hostile environments.